1. Enable Search Engine Friendly (SEF) URLs
Look in system -> Global Configuration -> SEO Settings and do as the following
- Search Engine Friendly URLs -> YES
- Use URL Rewriting -> YES (You need to rename the htaccess.txt to .htaccess before activating)
2. Using Joomla! 3 SEO Components
JoomSEF: SEO component to make your Joomla! URLs SEF (search engine friendly) and easily human understandable with metadata generation capabilities. Supports URL translations at multilingual sites using JoomFish/Falang. Online upgrades and extension instalation. Custom 404 Page Not Found, duplicate URLs management.
sh404SEF: sh404sef helps you improve your search engine rankings and get more traffic to your website. Satisfy many of the Google recommendations for search engine optimization with just a few clicks. sh404sef also includes many security features.
ACESEF - JOOMLA SEO & SEF URLS: AceSEF is a flexible and powerful Joomla SEF URLs, Metadata, Sitemap and Tags generator with an easy-to-use graphical user interface that simplifies the management of your site's SEO rank.